heh heh, Google is a wonderful tool.
Our backyard is overrun with the furry little nuisances, but unfortunately we don't own a BB gun!
At one time we thought we had only 7 or 8 of the little buggers. Dad finally decided he wasn't going to take it anymore and got out the shotgun. He got 15 out of 16 (a cat got the 16th) and they still kept coming! So unless you're going to camp out 24/7 (we probably have flying squirrels that work the night shift) even a shot gun won't do you any good.